Fastener holding power tool



June 6, 1967 K. R. BANGERTER ETAI. 3,323,394

FASTENER HOLDING POWER TOOL i 3 Sheets-Sheet 1 Filed oct. 2o, 1965 ggaiia" Alfffdr, Y :Il h

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INVENTORS KENNETH BANGERTER HARRY S. BENNETT "ATTORNEY ,June- 6 1967 K. R. BANGERTER ETAL 3,323,394

FASTENER HOLDING POWER TAOOL Filed Oct. 20, 1965 3 Sheets-Shea?l 2 INVENTORS KEN/verh' n. BAA/65mm HA my s. BEN/verf BY F/G. 4 @M w. rw

ATTORNEY June 6, 1967 K. R. BANGERTER ETAL 3,323,394

FASTENER HOLDING POWER TOOL Filed Oct. 20, 1965 3- Sheets-Sheet 5 INVENTORS KENNETH BANGERTER HARRY S. BENNETT BY QM wfP-MJI:

ATTORNEY United States Patent Office 3,323,3@4 Patented June 6, i967 3,323,394 FASTENER HOLDEN@ IWER TOOL Kenneth R. Bangerter, ithaca, NX., and Harry S. Bennett, Sayre, Pa., assignors to Ingersoll-Rand Company, New York, NX., a corporation of New Jersey lFiied Oct. 20, 1965, Ser. No. 498,982 Ciaims. (Cl. 81-52.3)

This invention relates to a portable fastener driving power tool and particularly to rotary impact tools.

When using conventional tools to turn a nut onto a bolt, it normally is necessary for the bolt to be held or locked against turning. If the bolt is not locked rigidly to the work piece by an anchoring means, the bolt is frequently held against turning by a second workman grasping the bolt head with a wrench located on the opposite side of the work piece from the operator driving the nut. In the latter case, each bolt-tightening operation requires the services of two workmen, one holding the power tool and the other one holding a wrench grasping the bolt head.

The principal object of this invention is to provide a power tool which simultaneously holds a fastener against turning while tightening a nut on the fastener.

Other important objects of this invention are: to provide a power tool containing a telescoping fastene-r holding member which retracts within the tool as a nut is tightened; to provide a power tool having a fastener holding member connected to the tool by a yieldable means which normally restrains the holding member against turning relative to the tool and which releases when the torque load on the member rises to a predetermined torque load; and to provide a power tool having a fastener holding member which can rotate relative to the tool when the torque load on the member reaches a predetermined torque load and which is adjustable to vary the torque load at which the fastener holding means is released to turn relative to the tool.

In brief, the objects of this invention are attained in a tool including a tool casing, a drive means including a hollow drive shaft mounted in the casing, a hollow spindle mounted in the casing in axial alignment with the drive shaft for holding a wrench socket, means contained in the casing connecting the drive shaft and the spindle for torque transmission therebetween, a fastener holding member extending axially through the hollow drive shaft in the hollow spindle with its front end projecting from the spindle and provided with locking surfaces such as flats for engaging corresponding surfaces on a fastener to prevent the fastener from rotating, said holding member being slidably mounted in the spindle to enable the retraction of said member rearwardly into the spindle, means urging the member forwardly to cause it to normally project from the spindle, and yieldable means connecting the holding member to said casing for restricting said member from turning relative to the casing when the torque load on the member is below a predetermined torque load. An adjustable means is provided for varying the predetermined torque load at which the holding member is released from the casing to turn relative to the tool casing. This adjustable means is arranged so that it can easily be adjusted from the exterior of the tool casing, without requiring any disassembly of the tool casing.

The invention is described in connection with the accompanying drawings wherein:

FIG. l is an elevational view with portions being cut away and shown in section of a rotary impact tool forming an embodiment of the subject invention;

FiG. 2 is an enlarged section taken along the line 2-2 of FIG. l;

FIG. 3 is an enlarged section taken along the line 3-3 of FIG. 1;

FIG. 4 is an elevational view with portions cut away of a second embodiment of the power tool made in accordance with this invention;

FIG. 5 is an enlarged section taken along the line 5-5 of FIG. 4;

FIG. 6 is an enlarged section taken along the line 6-6 of FIG. 4;

FIG. 7 is an elevational view, with portions cut away to show underlying sections, of a third embodiment of power tool having a motor mounted at right angles to the tool spindle; and

FIG. 8 is a fragmentary section taken along line 8-8 of FIG. 7.

The impact tool 1 shown in FIG. 1 includes a conventional tool casing 2 having a front nose 3 at its forward end and a handle 4 at its rear end. The handle 4 is shown with a conventional throttle or trigger 5 and an inlet fitting 6 adapted to be connected to an air line (not shown) for supplying fluid pressure to the tool 1. All of the foregoing structure is conventional in airpowered portable tools.

The casing 2 contains a conventional air motor 8 having a hollow drive shaft 9. The tool further includes a hollow spindle 10 rotatively mounted in the casing nose 3 and having a front end provided with flats 11 adapted to receive a conventional wrench `socket 12. Normally, the front end 11 of the spindle 10 will have a square cross section for keying it in the rear end of the wrench socket 12. Instead of a square cross section, the spindle of some wrenches has a splined cross section.

The drive shaft 9 is interconnected to the spindle 10 lby a conventional rotary impact tool mechanism 14 which includes a hammer 15 splined on the front end of the drive shaft 9 and an anvil 1-6 xed on the rear end of 'the spindle 10. Since the particular form of impact mechanism 14 f-orms no part of this invention, it will not be specifically described. A detailed description `of the impact mechanism 14 is found in Patent No. 3,174,559, issued to I. S. Vaughn on Mar. 23, 1965.

The drive shaft 9 contains an axial bore 17. The impact mechanism 14 contains `an axial bore 18 which is axially aligned with an axial bore 19 provided in the spindle 1t). An elongated fastener holding lmember or bar 20 is slidably mounted in the bores 17, 1.8 and 19 in the drive shaft, impact mechanism, and spindle, as shown in FIG. l. The front end of the bar 20 is -provided with a screwdriver tongue 21 adapted to fit in the kerf provided in the end of the stem of a bolt 22 for holding the bolt 22 against turning while the nut 23 is tightened on the bolt 22. The bar 20 is urged forwardly in the tool by a spring 24 which engages at its front end a split ring 25 mounted -on the lbar 20. The rear end of the spring 24 engages the end of a hollow sleeve 27 rotatably mounted in the rear end of the motor 8.

The rear portion of the bar 20 is slidably received in the front end of the hollow sleeve 27 and is keyed therein by having a hexagonal cross section engaging a corresponding hexagonal bore provided in the front end of the hollow sleeve 27. The rear end of the hollow sleeve 27 is xed to a brake disc 28 located in a chamber 29 disposed at the rear of the motor S. A friction disc 31B is pressed against the rear face of the brake disc 28 by a Belleville spring 31. The friction disc 30 is keyed to the tool casing 2 by a pin 32, thus preventing the friction disc 30' from rotating relative to the tool casing 2.

The force exerted by the spring 31 against the friction disc 30 is varied Iby an adjusting screw 33 threaded into the rear end of the tool casing 2 and engaging the center of the spring 31. As a result, the spring force on the friction disc 30 engaging the bra-ke disc 28 can be varied by adjusting the screw 33 which, in turn, varies the force restraining the bar 20 against turning in the tool casing 2.

As a nut 23 is turned on a fastener or bolt 22 and the stern of the bolt progressively extends deeper into the socket y12, the bar 2t) can slide rearwardly in the tool by means of the sliding engagement between the rear end lof the bar 20 and the hollow sleeve 27.

Operation In loperating the tool 1, it is first manipulated to place the socket 12 over a nut 23 which has been previously started on a bolt 22 located in a work piece 35. At the same time the tongue 21 of the bar 20 is pressed against the front end of the bolt stem 22. Thereafter the tool trigger is operated to start the motor 8, causing the impact tool to begin turning the socket 12. As the bolt 22 begins to turn, a kerf in the bolt steam is brought into alignment with the tongue 21 which then drops into the kerf. Thereafter, as the nut 23 is run down on the bolt 22, the bolt 22 is held against rotating by the bar 20 which restrains it by means of the yieldable brake composed of the brake disc 2S, the friction disc 30 and the spring 31 located at the rear of the tool casing 2.

Ultimately, the run-down yphase of the bolt turning operation 4comes to an end, and the nut 23 is tightened on the bolt 22 by a series of impact blows. As the torque load on the bolt-holding member rises, i-t is arranged to rotate relative to the tool casing 2 by the slipping of the brake disc 28 at the rear end of the tool. In many cases, the member 20 will not slip -because the bolt 22 is sufficiently tight in the work piece 35 for it to anchor itself without applying sufficient torque to the bar 20` to cause it to slip in the tool casing. As the nut 23 is run down and the bolt stem 22 projects progressively into the depth of the socket 12, the bar 20 is forced rearwardly in the tool casing. This rearward movement is provided by the bar 20 slipping and retracting into the hollow sleeve 27.

Second embodiment-FIGS. 4 I0 6 The second embodiment 37, shown in FIGS. 4 to 6, is very similar to the rst embodiment, with the exception that the second embodiment eliminates the use of the hollow sleeve 27 and keys the bar 20 directly to the vbrake disc 28 `by a slidable joint which allows the bar 20 to slide rearwardly through the brake disc 28 while being keyed to it, so that the brake disc 28 is able to restrain the bar 20 against turning relative to the tool casing. A spring 38 located rearwardly of the rear end of the bar 20 urges the bar 20 forwardly in the tool. The s-pring 38 is housed in a hollow pocket 39 provided in an adjusting knob 40` -threaded into the rear of the tool casing and used for adjusting the biasing force provided by the Belleville spring 31 engaging the friction disc 30.

Third embodiment-FIGS. 7 cmd 8 The third embodiment of impact wrench 42 shown in FIGS. 7 and 8 differs from the earlier embodiments by having the motor 8 mounted in the casing 2 at right angles to the impact mechanism 14. The motor 8 includes a bevel pinion 43 engaging a bevel gear 44 keyed on a hollow drive shaft 45, The drive shaft 45 drives the hammer 15 through a planetary gear reduction `system 46 which is conventional in the impact tool art.

A hollow tube 47 is rotatably mounted in the impact mechanism 14 and carries the fastener holding bar 20 which is keyed in the tube `47 and can telescope therein. A spring 48 is located in the tube 47 to bias the bar 20 forwardly to a fully extended position.

The rear end of the tube 47 is locked to an extension shaft 49 extending rearwardly through the hollow shaft 45. The rear end of the extension shaft 49 carries a detent wheel Sti having several ball seats 51 spaced around its circumference. A detent ball 52 is urged by a spring 53 into one of the ball seats to restrain the detent wheel from turning. The tension on the spring 53 is adjustable by means of a screw 54 threaded into the housing 2. Restraining the wheel 5t] from turning also restrains the fastener holding bar 2t), since the bar 2?, tube 47, exten- `sion shaft 49 and wheel 5t) are keyed or locked together against relative rotation. Varying the tension on the spring 53 will vary the value of torque required to release the detent wheel 50 from the detent ball 52.

Although a plurality of embodiments of the invention are illustrated and described in detail, it will be understood that the invention is not limited simply to these embodiments, but contemplates other embodiments and variations which utilize the concepts and teachings of this invention.

Having described our invention, we claim:

1. A rotary power tool comprising:

a tool casing;

drive means including a hollow drive shaft mounted in said casing;

:a hollow spindle mounted in said casing in axial alignment with said drive shaft for hold-ing a Wrench socket;

a mechanism contained in said casing interconnecting said drive shaft and said spindle for transmitting torque to said spindle;

a fastener holding member extending axially through said hollow drive shaft and said hollow spindle;

said member having its front end projecting from said spindle and provided with means for engaging a fastener to prevent the fastener from rotating relative to said member;

said member being slidably mounted in said spindle to enable the retraction of said member rearwardly into said spindle; j

means urging said member forwardly to cause it to normally project from said spindle; and

yieldable means connecting said member to said casing for restricting said member from turning relative to said casing when the torque load on said member is below a predetermined torque load.

2. The rotary power t-ool of claim 1 where-in:

said yieldable means includes a friction brake which allows said member to rotate relative to said casing when the torque load on said member rises to said predetermined torque load.

3. The rotary power tool of claim 2 wherein:

said yieldable means includes an adjustable means for varying the predetermined torque load at which said member is allowed to turn relative to the casing.

4. The rotary -power tool of claim 3 wherein:

said adjustable means is arranged to be adjusted from the exterior of said casing.

5. The rotary power tool of claim 4 wherein:

said mechanism is an impact mechanism for delivering a series of rotary impacts to said spindle.

References Cited UNITED STATES PATENTS JAMES L. JONES, JR., Primary Examiner. 

1. A ROTARY POWER TOOL COMPRISING: A TOOL CASING; DRIVE MEANS INCLUDING A HOLLOW DRIVE SHAFT MOUNTED IN SAID CASING; A HOLLOW SPINDLE MOUNTED IN SAID CASING IN AXIAL ALIGNMENT WITH SAID DRIVE SHAFT FOR HOLDING A WRENCH SOCKET; A MECHANISM CONTAINED IN SAID CASING INTERCONNECTING SAID DRIVE SHAFT AND SAID SPINDLE FOR TRANSMITTING TORQUE TO SAID SPINDLE; A FASTENER HOLDING MEMBER EXTENDING AXIALLY THROUGH SAID HOLLOW DRIVE SHAFT AND SAID HOLLOW SPINDLE; SAID MEMBER HAVING ITS FRONT END PROJECTING FROM SAID SPINDLE AND PROVIDED WITH MEANS FOR ENGAGING A FASTENER TO PREVENT THE FASTENER FROM ROTATING RELATIVE TO SAID MEMBER; SAID MEMBER BEING SLIDABLY MOUNTED IN SAID SPINDLE TO 